Composition for removing adherent deposits from internal-combustion engines



Patented Mar. 16, 1954 COMPOSITION FOR DEPOSITS FROM I ENGINES REMOVINGADHERENT NTERNAL-COMBUSTION Howard W. Pearsall, Highland Park, Mich.,as-

signor to General Motors Corporation, Detroit, Mich, a corporation ofDelaware No Drawing. Application June 28, 1950, Serial No. 170,948

Claims.

This invention relates to the removal of deposits of carbon and othersubstances, and particularly to improvements in compositions of matterfor loosening these deposits and to a process for eifecting the removalthereof.

The principal object of the invention is to provide a liquid mixturewhich may be employed to effectively loosen the carbon and otheradherent deposits from the surfaces of metal parts, such as combustionchambers, pistons, cylinder heads and valves, of an internal combustionengine. A. further object of the invention is to provide such acomposition which is inexpensive, efficient and has no detrimentaleffects upon the metal parts or crankcase lubricant with which it comesinto contact.

It is well-known that solid deposits, consisting principally of carbonand other products of the.

combustion of the fuel mixtur and lubricating oil, adhere to the pistonheads and other interior parts of internal combustion engines to thedetriment of efiicient engine operation. These deposits usually decreasethe life of the exhaust valves, lower the efiiciency of heat transfer tothe cooling jacket, reduce the capacity of the engine to take in a fullcharge of air and fuel, and, in the case of Otto cycle engines, increasethe tendency of the fuel to detonate or knock. It follows, therefore,that a means of easy and efiective removal of such deposits is of greatvalue, particularly if such means can be employed without disassemblingthe engine as is customarily required. Moreover, it appears likely thatif engine manufacturers could be assured that an easy method of removingcombustion chamber deposits were available to the public, they wouldfeel free to build engines having higher compression ratios andtherefore of higher efii ciency, with consequent great benefit to engineusers in the future.

In general, this invention materially facilitates deposit removal byproviding liquid mixtures comprised of mono-alkyl ethers of glycols,especially the mono-alkyl ethers of ethylene glycol and diethylenglycol; lower-alkyl substituted benzenes; and an alkyl ester of a fattyacid. The lower-alkyl substituted benzenes which I found to be ofparticular value were toluene and homologues thereof having a total of 7to 10 carbon atoms, xylene and aromatic high-flash solvent naphthasbeing examples of these homologues which proved highly satisfactory.All-of the aforementioned materials, when first combined, readily form ahomogeneous mixture which is ready for immediate use.

Among the esters which I have found to be of particular value are the1-to-6 carbon alkyl esters of a fatty acid having 14 to 18 carbon atoms.Examples of the latter are methyl ricinoleate and ethyl ricinoleate, theaddition of only a relatively small amount of these esters greatlyenhancing the deposit-loosening qualities of the mixture, apparentlybecause of a wetting or penetratingproperty possessed by such esters.

In accordance with the invention, I have found that a mixture ofethylene glycol monomethyl ether, xylene, and methyl or ethylricinoleate is effective in the removal of carbon and other adherentdeposits from the interior of internal combustion engines. I have alsofound that the utility of this mixture as a carbon remover is furtherincreased by the addition of substantial amounts of diethylen glycolmonomethyl ether and of an aromatic high-flash solvent naphtha, thesesubstances being less volatile than xylene and ethylene glycolmonomethyl ether. The high-ilash solvent naphtha employed is a coal tardistillate boiling between 250 F. and 490 F.

The application of highly volatile solvents to hot surfaces tends tovaporize and disperse them before they can exert much solvent effect.Less volatile solvents, on the other hand, although having less tendencyto immediately vaporize, normally do not have as great a solvent poweras do the more volatile compounds. As stated above, however, I haveprovided a unique and efiicient mixture of high-boiling and low-boilingsolvents Which is particularly suited for the removal of theobjectionable carbon deposits. In this mixture, the advantages of highsolvent power possessed by the lower-boiling, low molecular weightsolvents are almost entirely retained, and at the same time the tendencyof these to be lost through quick vaporization is materially decreasedby the presence of the higher-boiling solvents.

As hereinbefore explained, the addition of particular lower-alkyl estersof long-chain fatty acids, such as methyl ricinoleate and ethylricinoleate, greatly increases the eiiectiveness of the mixture becauseof the wetting action thereby provided. I have found these surfaceactive agents to be effective within the practical addition limits of0.1% to 10% by volume of the aforementioned mixture, approximately 2% byvolume being the optimum amount to be added. Additions of this agent tothe above mixture in a quantity beyond 10% by volume appears to createno additional beneficial results.

In accordance with these findings, I hav obtained commercially practicalresultswith a mix ture comprising approximately 25% to by volume oflower-alkyl substituted benzenes, to 75% by volume of mono-alkyl ethersof glycols, and 0.1% to 10% by volume of a loweralkyl ester ofricinoleic acid. Thus a mixtur of 49% of ethylene. glycol. monomethyl.ether, 49% of xylol, and. 2% of the ricinoleate proved satisfactory andhad good deposit-loosening properties. As hereinbefore explained,moreover, I have found that the addition of an aromatic high-flashsolvent naphtha boiling between 250 F. and 400 F. and diethylene glycolmonomethyl ether further increases the solvent action of the mixture.Outstanding results, for example, are achieved with a mixtur havingapproximately equal proportions of the four major constituents, or onein which the proportions of these constituents are varied within onlyrelatively restricted limits, such as one comprising 12% to 38% byvolume of Xylene, 12% to 38% by volume of. ethylene glycol monomethylether, 12% to 38% by volume of the aromatic high-flash solvent naphtha,and 2% to 38% by volume of diethylene glycol monomethyl. ether, towhich. mixture is added, 01% to 10% by volume of methyl or ethylricinoleate.

Ordinarily, the best method of using the aforementionedd'eposit-removing solution is to apply it to the coated parts. withoutdisassembling the engine, after these parts have become heated by actualoperation of the engine. Thus, in watercooled engines, the coolant inthe cooling jacket should be above 150F.

By way of example, we. may form a mixture of 24.5% by volume of ethyleneglycol monomethyl ether, 24.5% by volume ofv diethylene glycolmonomethyl ether, 24.5% by volume of xylene, 24.5% by volume of thearomatic high-flash solvent naphtha, and. 2% by volume of methylricinoleate, which compounds are mutually soluble, and then inject to 90milliliters of this composition into the combustion chamber of eachcylinder. This is preferably done after the engine has been operated fora period of time so that the coated metal parts become heated.Specifically, one of the best methods for applying the mixture to theengine is to slowly introduce asuitable quantity of it into thecarburetor air intake while the engine is idling, the last onefourth toone-sixth of the liquid being added at such an increased rat as to stallthe engine.

The mixture is permitted to act on the deposits for a suitable period oftime, depending upon the nature of the coating to be removed. In mostcases, I have found that from about one to six hours'is a sufiicientlength of time to obtain exoellentresults. The engine is then startedand the loosened carbon and other deposited particles are blown outthrough the exhaust.

As an alternative, the coated parts may be removed from the engine andheated over a flame or otherwise, the carbon-removing compositionapplied by immersion, spraying, painting, or other suitable means, andthe loosened deposit wiped, brushed or blown from the metal surfaces.Although heating accelerates the solvent action and thereby reduces thenecessary period of solvent activity, the mixture may be applied to thecoated parts at ordinary temperatures.

It is to be understood that while the invention has been described inconjunction with certain specific examples, the scope of the inventionis not to be limited thereby except as defined in the appendedclaim's.

I claim:

1. A composition for removing adherent deposits from surfaces ofinternal combustion engines comprising, by volume, 25% to 75% oflower-alkyl substituted benzenes having a total of 7 to 10 carbon atoms,25% to 75% of at least one glycol monomethyl ether and. 0.1% to 10% ofa. lower-alltyl ester of ricinoleic acid.

2. A composition for removing adherent deposits from metal surfacescomprising, by volume, 25% to 75% of at least one glycol monomethylether, 25% tov 75% of at least one lower-alkyl substituted benzeneselected from the class consisting of xylene and an aromatic high-flashsolventnaphtha boiling between 250 F. and 400 F., and 0.1% to 10%-of alower-alkyl ester of ricinoleic acid.

3. A composition for removing carbon and like deposits from metallicsurfaces comprising, by volume, 25% to 75% of ethylene glycolmonomethyl. ether, 25% to 75% of xylol, and 0.1% to 10% of an ester ofthe class consisting of methyl rieinoleate and ethyl ricinoleate.

4. A composition for removing carbonaceous deposits from metallic.surface comprising, by volume, approximately 49% of ethylene. glycolmonomethyl. ether, 49%. of xylol and 2% of. an ester of. the classconsisting of methyl ricinoleate and ethyl ricinoleate.

5. A. composition for removing carbonaceous deposits from surfaces ofinternal combustion engines comprising, by volume, 25% to 75% of alower-alkyl substituted benzene having a totalof 7 to 10 carbon atoms,25% tov 75% of an ether of the class consisting of ethylene glycolmonomethyl ether and diethylene glycol monomethyl ether, and 0.1% to 10%of a. lower-alkylester of ricinoleic acid.

6. A composition for removing organic deposits from the walls of enginecombustion chambers comprising, by VOlllIIlG, 25% to 75% of a loweralkylsubstituted benzene having a total of 7 to 10 carbon atoms, 25% to 75%of a mixture of ethylene glycol monomethyl ether and diethylene glycolmonomethyl ether, and 0.1 to 10% of an ester of the class consisting ofmethyl ricinoleate and ethyl ricinoleate.

7. A composition for removing carbonaceous deposits from surfacesofinternal combustion engines comprising, by volume, 25% to 75% ofmonomethyl ether of glycol, 25% to 75% of a mixture of xylol and anaromatic high-flash solvent naphtha boiling in the range between 250 F.and 400 F., and 0.1% to 10% of an ester of the class consisting ofmethyl ricinoleate and ethyl ricinoleate.

8. A composition for removing organic deposits from surfaces of internalcombustion engines comprising, by volume, 12% to 38% of xylene, 12% to30% of an aromatic high-flash solvent naphtha boiling in the rangebetween 250 F. and 400 F., 12% to 38% of ethylene glycol monomethylether, 12% to 38% of diethylene glycol monomethyl ether, and 0.1% to 10of methyl ricinoleate.

9. A liquid organic solvent. for removing adherent depositsfrom-internal combustion engines, comprising substantially equalproportions by volume of xylene, an aromatic high-flash solvent naphthaboiling between 250 F. and 400 F., ethylene glycol monomethyl ether anddiethylene glycol monomethyl ether, and 0.1% to 10% by volume of methylricinoleate.

10. A composition for removing deposits from combustion chambers ofinternal combustion engines comprising, by volume, approximately 24.5%of ethylene glycol monomethyl ether,

24.5% or dlethylene glycol monomethyl ether, 24.5% of xylol, 24.5% of anaromatic high-flash solvent naphtha boiling between 250 F. and 400 F.,and 2% of methyl ricinoleate.

11. A method of removing deposits from surfaces of internal combustionengines which comprises applying to the deposit a mixture comprisingapproximately 25% to 75% by volume of lower-alkyl substituted benzenehaving a total of 7 to 10 carbon atoms, 25% to 75% by volume of at leastone glycol monomethyl ether and 0.1% to 10% by volume of a lower-alkylester of ricinoleic acid, and removing the loosened deposits.

12. The process of removing organic deposits from the combustion chamberof an internal combustion engine which comprises applying to the deposita mixture consisting essentially of 12% to 38% by volume of xylene, 12%to 38%. by volume of an aromatic high-flash solvent naphtha boilingbetween 250 38% by volume of ethylene glycol monomethyl ether, 12% to38% by volume of diethylene glycol monomethyl ether, and 0.1% to 10% byvolume of a lower-alkyl ester of ricinoleic acid, and removing theloosened deposit.

13. The process of removing organic deposits from the combustion chamberof an internal combustion engine which comprises heating the coatedparts, applying to the deposit a mixture consisting essentially of 0.1%to 10% by volume of methyl riclnoleate and approximately equalproportions of xylene, an aromatic high-flash solvent naphtha boiling inthe range between F. and 400 F., 12% to lit 250 F. and 400 F., ethyleneglycol monomethyl ether, and diethylene glycol monomethyl ether. andremoving the loosened deposit.

14. A composition for removing adherent deposits from metal surfacescomprising, by volume, 25% to 75% of a mixture of lower-alkylsubstituted benzenes each having a total of 7 to 10 carbon atoms, 25% to75% of a mixture of glycol monomethyl ethers, and 0.1% to 10% of atleast one member selected from a class consisting of methyl ricinoleateand ethyl ricinoleate.

15. A composition for removing adherent deposits from metal surfacescomprising approximately 12% to 38% by volume of xylene, 12% to 38% byvolume of an aromatic high-flash solvent naphtha boiling between 250 F.and 400 F., 12% to 38% by volume of ethylene glycol monomethyl ether,12% to 38% by volume of diethylene glycol monomethyl ether and 0.1% to10% by volume of a lower-alkyl ester of ricinoleic acid.

HOWARD W. PEARSALL.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,820,395 Lovell et a1. Aug. 25, 1931 2,168,024 Ensminger Aug.1, 1932 2,236,590 Backofl et a1. Apr. 1, 1941 2,251,988 "Curran Aug. 12,1941 2,474,437 Potter et a1. June 28, 1949

1. A COMPOSITION FOR REMOVING ADHERENT DEPOSITS FROM SURFACES OF INTERNAL COMBUSTION ENGINES COMPRISING, BY VOLUME, 25% TO 75% OF LOWER-ALKYL SUBSTITUTED BENZENES HAVING A TOTAL OF 7 TO 10 CARBON ATOMS, 25% TO 75% OF AT LEAST ONE GLYCOL MONOMETHYL ETHER AND 0.1% TO 10% OF A LOWER-ALKYL ESTER OF RICINOLEIC ACID. 